despondency vs melancholia

despondency

noun
  • A feeling of depression or disheartenment. 

  • The loss of hope or confidence; despair or dejection. 

melancholia

noun
  • depression, characterised by irrational fears, guilt and apathy 

  • Deep sadness or gloom; melancholy 

How often have the words despondency and melancholia occurred in a corpus of books? (source: Google Ngram Viewer )